Can't get LinqDataSource to recognize deatil relations

Question

what I have are two tables, Publication and DTPersonnel. Publication has a primary Key and the other (DTPersonnel) has a field that is link back Publication. I sent up a DBML layout for my LinqDataSource and link the two tables.. I have added the LinqDataSource component to my web page and (for testing) a label.

I then set up the label data-binding to point to a field in DTPersonnel.DTRoleID like this:

 <asp:FormView ID="FormView1" runat="server" AllowPaging="True" 
        DataSourceID="LinqDataSource1">
        <ItemTemplate>
            <asp:Label ID="Label1" runat="server" 
    Text='<%# BIND("DTPersonnels.DTRoleID") %>'></asp:Label>
        </ItemTemplate>
    </asp:FormView>
    </asp:Content>

My LinqDataSource is setup like this:

<%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Layout.aspx.cs" Inherits="AequorPubTracker.Account.Layout" %>
<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
    <asp:LinqDataSource ID="LinqDataSource1" runat="server" 
        ContextTypeName="AequorPubTracker.LayoutDataContext" EntityTypeName="" 
        onselecting="LinqDataSource1_Selecting" TableName="Publications" 

        Select="new (DTPersonnels.DTRoleID,PublicationID, DTPersonnels, ActLAYDate, ActRRIPDate, ActPPIDate, ActPPODate, ActECTWDate, TargetECTWDate, TargetPPIDate, TargetRRIPDate, TargetPPODate, TargetLAYDate)">
    </asp:LinqDataSource>

But when I run the app in the browser I get the following error:

Exception Details: System.Web.Query.Dynamic.ParseException: No property or field 'DTRoleID' exists in type 'EntitySet`1'

I hope I gave enough information any help would be great.

Answer 1

I assume since you are specifying the select clause, this is a read-only view of the data. If that is so, your problem has a fairly straightforward solution. However, if it is not so (of which I am uncertain since that your code calls the Bind method rather than Eval), there is more complex handling required to update related fields as a LinqDataSource with the Select member specified cannot allow updating.

Ensure you select the DTPersonnels member in your clause, but remove DTPersonnels.DTRoleID from the selection. If you call Eval("DTPersonnels.DTRoleID") it will display the related record's member value.

I presume, however, there is also a problem in the configuration of your schema file. From what I can infer, you expect there to be a 1-to-1 relationship between Publications and DTPersonnel. However, since the error indicates that there is no member on EntitySet, that implies that you have allowed a 1-to-many relationship where Publications have many DTPersonnel. If there is not a 1-to-1 relationship, your code will not be able to determine which related record's DTRoleID to display.

If you actually DO intend for there to be many DTPersonnel related to a Publication, then you may want to approach this from the other way around of displaying a list of DTPersonnel and showing their related Publication's data instead.

Answer 2

If you're wondering where the error itself is coming from, it's located here:

Select="new (DTPersonnels.DTRoleID,PublicationID, DTPersonnels, ActLAYDate, ActRRIPDate, ActPPIDate, ActPPODate, ActECTWDate, TargetECTWDate, TargetPPIDate, TargetRRIPDate, TargetPPODate, TargetLAYDate)">

Since you are selecting data from the Publications table, it is looking for a field "DTRoleID" there. I'm guessing that table does not have a "DTRoleID" field, causing the error you are receiving.